Allow dropping of files onto window

src/app.cpp

@@ -8,7 +8,10 @@ App::App(int argc, char *argv[]) :
     QApplication(argc, argv), window(new Window())
 {
     window->show();
-    window->load_stl(":gl/sphere.stl");
+    if (argc > 1)
+        window->load_stl(argv[1]);
+    else
+        window->load_stl(":gl/sphere.stl");
 }
 
 bool App::event(QEvent* e)

src/window.cpp

@@ -14,6 +14,7 @@ Window::Window(QWidget *parent) :
 
 {
     setWindowTitle("fstl");
+    setAcceptDrops(true);
 
     QFile styleFile(":/qt/style.qss");
     styleFile.open( QFile::ReadOnly );
@@ -128,3 +129,18 @@ bool Window::load_stl(const QString& filename)
     loader->start();
     return true;
 }
+
+void Window::dragEnterEvent(QDragEnterEvent *event)
+{
+    if (event->mimeData()->hasUrls())
+    {
+        auto urls = event->mimeData()->urls();
+        if (urls.size() == 1 && urls.front().path().endsWith(".stl"))
+            event->acceptProposedAction();
+    }
+}
+
+void Window::dropEvent(QDropEvent *event)
+{
+    load_stl(event->mimeData()->urls().front().toLocalFile());
+}

src/window.h

@@ -12,6 +12,10 @@ public:
     explicit Window(QWidget* parent=0);
     bool load_stl(const QString& filename);
 
+protected:
+    void dragEnterEvent(QDragEnterEvent* event);
+    void dropEvent(QDropEvent* event);
+
 public slots:
     void on_open();
     void on_about();